What is B-A ?

Question

Hello

I think angle b = 2 x angle A. So B should be sufficient?

Thanks

jamifahad · Answer

This is true only when triangle is inscribed inside a circle with center as R.

Also, OA is A.

melguy · Answer

Thanks for clarifying.

Grockit advises that OA is E. What am I missing?

Thanks

jamifahad · Answer

Oh sucks!

It is E. Because if you do the calculation b-a will come in terms of one of the base angle i.e <X or <Y. which is unknown.

IanStewart · Answer

This question is almost an exact copy of Q140 in the DS section of OG12. Are they charging money for these questions?

In any case, even with both statements, you can put point R very close to line XZ, in which case angle b will be very close to 180 degrees, or you can put point R very close to point Y, in which case b will be very close to 50 degrees, so the information is not sufficient, and the answer is E.

gaurav1083 · Answer

IMO E:
It is not mentioned which 2 sides are of same length. Hence not possible to find the value of b-a.

metallicfacez · Answer

E for me... here is how I approach questions like this. Let's assume the outer triangle stays the same, and you raise point R (of the inner triangle). The value of angle "b" will change, while statements (1) and (2) remain to be true. That tells me the value of b-a cannot be determined... hope this helps.

What is B-A ?

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